Distillation of oil-shale



Oct. 20, 1953 E. s. PETTYJOHN 2,656,308

' DIsTILLATIoN 0F OIL-SHALE Filed Sept. 16, 1950 l ff? u l Patented Oct. 20, 1953 UNITED STATES TENT OFFICE DISTILLATION OF OIL-SHALE Application September 16, 1950, Serial No. 185,273

2 Claims.

art methods suffer from a, serious disadvantage.`

It is somewhat difficult to disintegrate oil shale nely, especially when the shale is rich in oil, since the organic matter present in the shale tends to cause the comminuted shale particles to adhere or stick together. Particularly at elevated temperatures, oil shale tends to become more or less gummy with resultant adhesion of the oil shale particles at devolatilizing temperatures.

I have now providedv method and apparatus for recovering the oil content of oil shale in which the shale is subjected to two successive disintegrating steps. Devolatilization is carried out concurrently with the second disintegrating step. Thereafter, the devolatilized shale and the volatile products are separated and the separateddevolatilized shale particles are uidized with a gas containing free oxygen at an elevated temperature for burning oif the residual carbonaceous matter in the shale. The hot combustion gases then generated are utilized in carrying out the disintegrating and devolatilizing steps. As will be disclosed in greater detail hereinbelow, no difficulties are encountered in Vmy process and apparatus due to sticking together of shale particles, and practically complete recovery of all Figure l is a side elevation, with parts shown in vertical section, of apparatus according to the present invention; and l Figure 2 is a cross sectional view taken aloner the une 2 2 of Figure 1.

Reference is made to the eopending application of John I. Yellott, Serial No. 762,589, en-V titled Comminution Device, led July 22, 1947, 'and' issued as Patent No. 2,515,541. This cosending applicaties discloses@ embinetonl with.

a flash pulverizing device for solid material capable of yielding an entrainment of comminuted solids in a streaming gas, of a vortex chamber arranged so as to receive said streaming entrainment in a generally tangential direction and at one side of the axis of said chamber, the latter being provided With a central axial discharge aperture. In this apparatus, granular solid material may be comminuted by a method described as follows. The flash pulverizing device includes a sour-ce of expansi'ble uid held under a pressure such that the liuid can be expanded with a pressure drop of atleast 15 lbs. per sq. in. rI'he compressed fluid is continuously discharged from this source into an elongated conduit, to form a stream of compressed iiuid flowing ata velocity less than one-half of the critical velocity but, in any event, at least suiiicient to suspend therein a granular solid permeable to the compressed huid. There is thus established a stream of compressed fluid iiowing in an elongated conduit and capable of being expanded with a pressure drop of at least 15 lbs. per sq. in. This stream of fluid is passed into a restricted area, such as a convergent nozzle or a restricted orifice, so as practically instantaneously to accelerate said uid to 'critical velocity and simultaneously to reduce the fluid pressure by at least 15 lbs. per sq. in. The fluid is discharged from the restricted area (the convergent nozzle or restricted orice) as by allowing the fiuid to escape into a divergent nozzle, into a conduit of at least the same diameter as the conduit upstream or the restricted area, or directly into the vortex chamber. Concurrently and continuously, solid granules are introduced into the flowing stream of compressed fluid sufliciently far upstream of the constricted area to suspend the solid granules in the flowing stream of compressed fluid'and to permit `acceleration of said granules by said streaming fluid in said restricted area. The amount of solid material introduced into the streaming fluidis limited so as not to prevent a pressure drop, at the restricted area, of at least l5 lbs. per sq. in. In general, less than 10 parts and preferably not more than 4 parts (by weight) of solids should be used to each part of fluid.

Then, on passing through and past the restricted area, the solid granules are shattered, probably due to the sudden expansion of the compressed fluid contained within the granules which are permeable to the compressed iiuid and are believed to have become permeated thereby while being lcontacted by the compressed fluid upstream of the restricted area,

aeasos Reference is made to the patent Yellott 2,515,542 which discloses and claims this method of flash pulverizing.

Thus, the flash pulverizing device yields an entrainment of comminuted solid particles moving rapidly but under lower uid pressure than the original entrainment of relatively coarse particles to be comminuted. The kinetic energy content of the entrainment of comminuted or shattered particles is utilized for further ccmminution in the vortex chamber. The ene trainment of comminuted or shattered particles is discharged, from. the flash pulverizing device, through a divergent nozzle, or through a short conduit l(mentioned hereinabove); or, preferably, directly, into the vortex chamber. This discharge is directed generally tangentially into they vortex chamber, so that rapidly flowing entrainvelopment of gumminess are encountered.

ment initially impinges against the chamber wall and then establishes a vortical or whirling flow in said chamber, which is: provided with an axial centralt discharge opening. Due to the vertical or whirling movement of the iiuid, the relatively lessfine shatteredparticles move radially out- Ward-1y within the vortex chamber, whilev the relativeliy fine particles tend to remain in the cen tralregion of! the vortex chamber and are discharged through the. central axial aperture.A The relatively less fine.v particles thrown radially out- Ward Within the. chamber by centrifugal force are carried around in the outer portion of the chamber and are there further comminuted by impact against the peripheral wall of the chamber and against other particles and by abrasion between said. outer wall and other particles. When thus. comminuted, disintegrated or worn down tosmaller particle size, theresulting smaller particles are discharged through the axial central discharge aperture.

Thus, in the. vortex chamber, the kinetic energy of the mixture of uid and solids issuing. from the constricted area in. the flash pulverizing conduit. is utilized` for further comminution in the vortex chamber.l directly receiving said mixture. as by impact, against the walls of the vortex chamber, by abrasion against the wall of the vortex chamber and by impact and/or abrasion between flash pulverized particles. Further, the vortex. chamber tends to separate the variously sized solid particles and to pulverize additionally the coarser of those particles by impact and/or attrition.

The present invention relates to a combination, with a modified form of the method and appara tus' of sai-d Yellott application, of additional steps and apparatus elements. The resulting combinations form novel method and apparatus particularly adapted. forthe recovery of the oil content of oil shale, as will be discussed in greater detail hereinbelow.

According tothe present invention, the temperature in the ,vortex chamber is maintained high. enough to bring about conversion into volatizable form of the organic matter present in the'shale and devolatilization of the shattered shale particles. VrThis)temperature may suitably range from 800 to 1500* F., and, preferably, from about 1000"' to 1200D F. For maintaining the vortex temperature at the indicated value, a suiiicient amount of l`io`t iuid is injected tangentally into the VCtexF Chamber. Both the :duid utilized in flash pulverizing the shale and the fluid injected intol the vortex chamber are sub@ stantially devoid of free oxygen. Therefore, combustion will not take place within the vortex' chamber. By suitable proporticnifng of the iiu'id y The effect Vof the elevated temperature within the vortex chamber is not merely that of volatilizing oily shale constituents. rFhus, mere raising of the temperature of the shale, particularly to Within the devolatilzation temperature, renders theshale more grindable and thus brings about a higher degree of comminution, all other factors being equal. Devolatilization also ren ders the shale more easily grindable. Further, rapid raising of the temperature of the flash pulverized shale particles to within the devolatil-ization temperature tends to generate vapor within the shale particles. Thus, if the evolution of vapor is sufciently rapid, the shale particles may be shattered explosively by the evolution of vapor within the particles. Such explosive shattering of the shale particles by vapor rapidly liberated Within the particles can be brought about at the beginning of the devolatilization, since the volatilization of. only a relatively small part of the volatile content of the shale will suffice to bring about the results described.

In general, both greater disintegration and more extensive devolatilization in the vortex chamber are favored by more rapid movement of fluid and solids. within the vortex chamber; by higherv temperature in the vortex chamber, by longer residence in the vortex temperature; and by a high ratio of fluid to solids in the vortex chamber. More extensive devolatilization is favored by ner particle size, both of the shale introduced into the vortex chamber and of the particles further comminuted within the vortex chamber. It will thus be understood that since many factors favor both finer particle size and more extensive devolatilization, there will be a tendency for any variation in any one factor in a direction favoring iiner subdivision to bring about a more extensive devolatilization at a rate that, at rst glance, may seem disproportionate to the extent of the variation. Thus, when a temperature Within the vortex chamber is raised to a relatively limited extent, the shale is rendered more easily grindable; more vapor is liberated, and liberated more rapidly, within the shale particles favoring explosive shattering'by the libera-ted vapor and more vapor is evolved from the particles, thus adding to the fluid content of the vortex and increasing the rate of movement Within the vortex. But, asa result of the iiner subdivision then obtained, devolati-lization will be more extensive which in turn lea-dsto liner subdivision so that the initial relatively limited temperature raised in the vortex chamber may ultimately cause a rather significantly finer subdivision and more extensive-devolatilization.

In brief, greater iineness and hence more extensive devola-tilization are brought about by the action of a number of concurrently effective factors including easier grinding due to elevated temperatura-shattering of.' particles by rapid generation of vapor Within the particles, and increased rate of movement Within the vortex due to liberation of' additionalvapor which' also increases the Il factorsfendstqaceieratejthe others so that the resulting changes may be said to vhe"self'accelerat- 'V complete combustion ofthe carbon contentof the" From devolatilization ofthe shale can be effected in the vortex'cham-be'r within arelatively short time.

l The preferred gas enteringthe flash pulverizing l `apparatus issuper-heated steam which canfeasily v be separated fr ornv the volatilized shale constituentS. gases can also be injected intothe/flash pulveriz- But, if desired, combustible orA inert ing apparatus, for instance, producergas. Steam or hot producer gas or preferably hot combustion gases can beinjected into the vortexP chamber.

A very important feature of r'the process step practicedwithinstheevortex ,chamber is the fact .that the shale, particles, although Within devolatilizing temperature, do not adhere or stick to each other or to the Walls 0f theapparatus. There are several possible explanations for this fact.

, ltwo streams enteringjthe apparatus and of the volatile constituents of the shale.

Downstream of the vortex chamber, means are provided for separation of fluid and solid material from the hot suspension discharged from the vortex cham-ber. The separated fluid is directed to a condenser, where the fluid is separated into liquid vand gaseous components. `The more or less oily liquid then obtained is the principal desired nnal product.

The, finely divided devolatilized shale (which contains residual non-volatile carbonaceous material) separated from the suspension issuing from the vortex chamber contains av considerable amount of heat. Both the carbon'content and the heat content of thisudevolatilized shale are re-4 coveredby transferring the separatedv nne shale into a uidizing chamber for traversal by an oxygen-containing gas such as air for combustion of the carbonaceous matter. The resulting combustion gases `may be utiliz-ed `directly for injection into the vortexchamber or may be utilized i for generating and superheating steam which is thensent throughthe disintegrating and devel# atili'zing means. e

I n effect, the devolatilized shale is charged into the combustion apparatus in preheated condition. Due to this preheatingl and'to the vfine subdivision of the shale, complete combustion of the carbonaceous material inthe shale can beeffected in spite of the factthat the Idevolatilize'dshalef contains ,relatively much more inorganic materialV than. car-bonacemsmaterial.` By other methods,

shalecannot' easilybe eifected. f

,The fcompletelywspent hot shalej, discharged v :from trie'niiidizipg chamber caribe subjected to heat exchange with ,airin a sfeoorid:fluidizing` for ,preliea.tin'g, this 1 1` which is then.

,ibaily Ione ofjthese r the tit apparent lthat, i according tomvinventiomne subdivision and f step enhanced.

is yrecovered and the e'fliciency f th":mbiis'tion Apparatus for carrying out the abvedi'sclosed process is shown inthe drawings".` There, the numeral I0 indicates a hopper *havingn aconical bottom for receiving coarsely fragmented'shale. The hopper II] is providedat' its discharge end with a double bell and hopper device II or other gas-lock means for discharge intcat'anllz having a conical bottom I3 discharging into 'a conduit I4. The latter communicates directly* with and serves to conduct the shale to be devolatilized into a horizontally extending tubularly enclosed screw feeder or conveyor I6, Adriven by amotor I'I. The screw conveyor I6 moves theshale, by way of avertical extension I6a, intoafhorizontally extending conduit A20. Steam, producer gas, combustion gas or other calorilic gasor inert gas or mixtures of such gases under pressure orother iluid substantially devoid of free oxygen are admitted into the left hand end of the conduit 20 ahead of a valve 20a and into the upperfportion of the tank I2 through a valved conduit `2I tapping the conduit 20. The right hand end portion of the conduit 20, downstream ofthe Adischarge opening of the screw conveyor AIB, is constricted, as at 25, to form a convergent-divergent'nozzle communicating directly and tangentially with a circular vortex chamber indicatecil generally by the reference numeral`30 and extending" in a generally horizontal axial direction. i More particularly, the vortex chamber 3 0 includesfspaced disc-shaped left and rightside Walls Selmand 32, together with an intermediate cylindricalflwall 33. The end of the nozzle25 is attachedetothecylindrical wall 33, preferably 'approximatelymidway between the side Walls 3 I and 3,2"soa`s to discharge into the chamber A30transverselyand to one side of the axis of the chamber 30. e v

A conduit 35 is adapted to discharge steam,

y combustion gas and producer gas or the-like, hot

fluid substantially devoid of free oxygen tangentially into. the chamber 30. V`The conduit 35 may have its discharge orcespaced `fromA the discharge orice`25fby 90, 180, 270; or asother- I wise desired.

The right hand lside Wallj 32 `of the l chamber 30 is formed withiacentral axialfaperture't discharging into a conduit 3T, 4which may` diseharge into a cyclone type orjj other separating ldevice 4B (for separating the comminuted devolatilized shale from' its liiuid'suspension mediurnXt'he devolatilized shale being` discharged thronghva conduit 4I, `and the fluid entraining'rnediumbeing discharged' throughja conduit' `2. i The latter, in turn, discharges the fluid into' aj condenser 3 from which liquid and gaseous products may be recoveredv separately. If steam is injected into the apparatus, the liquid products will include water which can be separated" rom'theliquid Vproducts by conventional methods. l Y

The hot devolatilizedfshale moves through the conduit 4I into'a receptaclell and from the latter through a valved 'conduitf into 'a riser 4l suitable source) isfadmitted into the riser il Vto carry the shale yinto theiiuidizing vesselwhere the shale forms a fluidiz'edbed'whichfisfmaintained at combustionk temperature forV burning off the carbon content of the devolatilizfeds'hale.

The spent or 'de carbonized shale overflows from the nuidizing vessei'dethrgh a'condutfas dischargingmthe shalejnto alri'sefrf for aI-second )f1-aiming vessel f; Air from any'I'stimata` source) is admitted into the riser 50 for carrying the spent shale up into the fluidizing vessel 50 where a heat exchange is effected between theV spent shale in the chamber leaves the latterV through a conduit 52 discharging into the cyclone separator 53 where any shale entrained by the preheated air is separated and returned to the fluidizing Vessel 5|. After passing through the separator 53, the preheated air moves through a conduit 55 into the riser l and into the fluidizing vessel 48.

The combustion gases generated within the first fluidizing Vessel 48 are discharged therefrom through a conduit 58, passed through a cyclone separator 59 for separating therefrom any entrained shale, which is returned to the fluidizing vessel 48 through a conduit 55. From the separator 59 the combustion gas passes into a conduit 62 which discharges into the conduit 35 through a valve 53. This valve is opened only when it is desired to inject the combustion gases directly into the vortex chamber 3D. A Valved conduit 65 branching oif from the conduit 52 admits combustion gas to a steam generator and/or superheater 66, from which the combustion gases are discharged through a conduit El. Water or steam is admitted to the steam generator and/or superheater 66 through a conduit 6B. Steam generated and/or super-heated in the element 66 is discharged therefrom through a conduit 69 having one valved branch 'lll discharging into the conduit 20 and another valved branch 1| discharging into the conduit 35.

If desired, steam to be superheated may be conducted through a conduit i2, a coil 'I3 within the iluidizing vessel 48, and through a valved conduit `|3 into the conduit 'l for discharge into the conduit 25.

At the start of the operation of the above described apparatus, shale in coarsely fragmented form is charged through the hopper I6 and the gas-lock into the tank I2. Moreparticularly. the shale should be capable of passing freely through the discharge orice 25. The shale granules should have their maximum dimension not in excess of one third of the orice diameter. Steam, combustion gas, producer gas or other calorifio gas or inert gas or mixtures of these fluids, under pressure, are introduced through the conduits 25 and 2| into the tank I2 and caused to flow through the conduit 2|). The screw conveyor I6 is operated to advance the shale to be disintegrated and devolatilized into the stream of fluid flow-ing through the conduit 20. The nozzle 25 is so spaced from the discharge opening of the screw conveyor |5 that the shale discharged into the conduit 20 will be accelerated to the point of entrainment by the fluid flowing through the conduit 20 before reaching the nozzle 25. Instantaneous expansion occurs continuously and uninterruptedly as the compressed fluid in the conduit 25 passes through y Y the nozzle 25 and causes shattering of the shale particles, apparently by virtue of the expansion of the compressed fluid contained within the porosities of the shale.

The operating pressure of the fluid in the conduit 2l) should be at least 15 pounds per square inch and may be as high as r150 pounds per square vinch or higher. At the preferred operating inch in the conduitl 20, as when the fluid is superheated steam as from 350 to 450, the pressure downstream of the nozzle 25 may suitably be less than A60 pounds per square inch, for instance, 5 pounds per square inch or less.

It should be understood that the pressure drop across the nozzle 25 should be such as to accelerate the uid owing through the nozzle to the critical velocity. Ahead of the nozzle 25, the iiuid may suitably iiow at from 10 to 400 ft. per second. The pressure upstream of the nozzle should be at least l5 pounds per square inch above the pressure downstream of the nozzle. The extent of comminution in the nozzle is determined, inter alia, by the pressure level of operation, by the difference between the upstream and the downstream pressures on the two sides of the nozzle 25, by the ratio of fluid to solids passing through the nozzle 25, and by the rate of movement of solids through the nozzle 25. Finer comminution is effected in the nozzle by the maintenance of maximum upstream and minimum downstream pressure, by the use of relatively large amounts of uid as compared to the amount of solids, and by the establishment of rapid flow of solids through the nozzle.

The streaming entrainment of comminuted shale issues from the nozzle 25 into the Vortex chamber 39 where the fluid forms an inwardly spiraling vortex. The fluid being introduced ows at a high rotative speed but at a low inward speed in said vortex so that the relatively less ne particles, under the action of centrifugal force, are kept in the peripheral portions of the Vortex chamber 30 Where they are further comminuted or disintegrated, by the initial impact upon the chamber wall, by further impact upon the chamber Wall (subsequent to the initial impact following discharge from the nozzle 25), by impact upon other particles or by attrition. Because of the high rotative rate of movement in the iiuid and its relatively low inward rate of movement, there is a strong tendency to return to the outer portion of the vortex for further grinding action, such relatively less fine particles as may be thrown or bound into, or otherwise may reach the inner portion of the vortex charnber. The relatively fine particles introduced through the nozzle 25, as well as the particles of similar neness resulting from further grinding of relatively less ne particles, are entrained by the fluid being discharged through the axial aperture 36 and are carried through the conduit 31 to the separator 40 for recovery through the conduit 4|.

The extent of comminution in the vortex chamber 30 is determined, inter alia, by the temperature of the fluid discharged into the vortex chamber (as will be discussed in more detail herein below), the rate of movement of the solid particles within the vortex chamber, the ratio of iiuid to solids, and the like. Fner comminution may be effected by rapid movement of solids and the use of large amounts of fluid as compared with the amount of solids introduced into the vortex chamber. Fluid tangentially admitted into the vortex chamber 30 through the conduit 35 contributes to the vortical movement of solid particles through the vortex chamber 3i).

Fluids are admitted into the system at two localities. First, the fluid required for iiash pulverization is admitted into the conduit 2U and there admixed with the shale. Additional amounts of fluid are admitted tangentially into accesos the `vortex chamber 3,0 throughl a conduit 35, under such pressure, at such velocity or with such momentum as may be requiredto overcome the internal pressure within the vortex chamber and, if desired, to increase the rate of flow within the` vortex chamber. The preferred compositions and the temperatures o f the fluids admitted at these two localities are discussed in the following paragraphs. j

The temperature of the fluid flowing lthrough the conduit 20 should be such that no clogging of the nozzle 25 will take place. This end will be attained if the temperature of the fluid admitted into the conduit 20 is kept below 600 F. and,V preferably, not higherthan 500 F. The exact maximum permissible temperature at the nozzle 25 and in the conduit 20 is determined by the temperature at which the shale turns sticky or gummy, which varies according to the originof the shale. The temperature in the `vortex chamber 30 is maintained, as disclosed hereinabove at a level where the shale will be devolatilized, for instance, at from 800 to1500 Frand, preferably, from about 1000 to 1200 F.

As disclosed hereinabove, more complete devolatilization inthe vortex chamber is favored, inter alia, by small particle size of the solid material, high temperature,` long time orf-residence of the solid material in the vortex chamber, the introduction of large amounts of uid into the vortex chamber, and the like. I, therefore, adjust the conditions t bring about small particle size, high temperature, long time of residence and/or introduction of relatively large amounts of uid, so as to bring about complete devolatilization of the shale.

The heat required for maintaining the indicated temperature in the vortex chamber is derived, as disclosed hereinabove, from the combustion of the devolatilized shale in uidized condition. For this purpose, the shale discharged from the vortex chamber should preferably be characterized by a particle size not greater than mesh and not less than 200 mesh. As also disclosed hereinabove, the heat of combustion may be utilized directly by injecting the combustion gases into the vortex chamber 30 through the conduit 62, the valve 53 and the conduit 35. A second method of utilizing the heat content of the combustion gases involves the generation of superheated steam in the element 05. The resulting superheated steam may be utilized both for flash pulverization and for maintaining the desired temperature in the vortex chamber, passing for these purposes through the conduit 59 and the conduit l0 into the conduit 20 and through the conduit 'H into the vortex chamber. If desired, superheated steam may be utilized only for ash pulverization while a part of the combustion gases are injected directly into the vortex chamber. Ordinarily sufiicient air is admitted into the first fluidizing chamber for combustion of the carbon content of the devolatilized shale substantially to carbon dioxide.

Many details of composition, structure and procedure may be varied within a Wide range without departing from the principles of this invention and it is therefore not my purpose to limit the patent granted on this invention otherwise than necessitated by the appended claims.

I claim:

1. The method of recovering oil from coarsely fragmented oil shale which comprises -providing a source of hot fluid substantially devoid of free pressure drop of at least lbs. per square'lnch; continuously .and uninterruptedly discharging said fluid from said .source while confining the discharged fluid sothat the` discharged confined fluid will flow at a substantially uniform velocity less thanthe critical velocity and with a pressure dropless than the critical pressure drop; thereafter continuously and uninterruptedly flowing said discharged iluid through a sharply vrestricted oxygen and capable of being expanded with a areaso as suddenly to accelerate said lluid to critical 4velocity' by instantaneously reducing the fluid pressure :by atleast 15 lbs. per square inch; concurrently, continuously and uninterruptedly introducing said shale, in the form of granules capable of freely passing through said restricted area, into said flowing conned lluid upstream of said restricted area; controlling the ilow off-said conned fluidfrom the point of introduction of said shale to said restricted area so that said shale will be entrained/ by said fluid; adjusting the amount of shale introduced into said fluid toa value lessthan 10 parts by weight for each part of fluid; said shale granules being subjected while entrained to the first acceleration tocritical Avelocity "of said fluid as said fluid ilowsfrom said source to and through said restricted area-whereby said granules are shattered and there is formed a. rapidly flowing suspension of shatterediparticles in expanded iluid; said shale up to this point being maintained at an elevated temperature below the temperature at which said shale particles tend to adhere together; confining said suspension within a cylindrical axially limited space while forming said suspension into a vortex, the rate of flow in said vortex being such that shattered particles are kept circulating within said space and thereby further comminuted; incorporating with said vortex additional uid formed as combustion gas during the combustion step recited hereinbelow and substantially devoid of free oxygen and sufciently hot to maintain the temperature in said vortex at a point where said shale will be devolatilized; withdrawing from the center of said vortex hot fluid having suspended therein relatively ne particles of devolatilized shale; separating said devolatilized shale from said hot fluid; condensing the oily fraction of said fluid to recover the oil content of said shale; and forming the separated devolatilized hot shale into a fluidized bed and burning olf the carbon content of said shale by flowing through said bed a gas preheated as recited hereinbelow and containing free oxygen; and forming the decarbonized shale into a uidized bed by flowing a gas containing free oxygen through said bed of decarbonized shale whereby said gas is preheated.

2. The method of recovering oil from coarsely fragmented oil shale which comprises providing a source of hot fluid substantially devoid of free oxygen and capable of being expanded with a pressure drop of at least 15 lbs. per square inch; continuously and uninterruptedly discharging said fluid from said source while confining the discharged iiuid so that the discharged confined uid will flow at a substantially uniform velocity less than the critical velocity and with a pressure drop less than the critical pressure drop; thereafter continuously and unlnterruptedly flowing said discharged fluid through a sharply restricted area so as suddenly to accelerate said lluid to critical velocity by instantaneously reducing the uid pressure by at least 15 lbs. per square inch; concurrently, continuously and uninterruptedly introducing said shale, in the form of granules capable of freely passing through said restricted area, into said flowing confined fluid upstream of said restricted area; controlling the flow of said confined fluid from the point of introduction of said shale to said restricted area so that said shale will be entrained by Said fluid; adjusting the amount of shale introduced into said fluid to a Value less than 10 parts by weight for each part of fluid; said shale granules being subjected while entrained to the rst acceleration to critical velocity of said fluid as said uid ilows from said source to and through said restricted area whereby said granules are shattered and there is formed a rapidly flowing suspension of shattered particles in expanded fluid; said shale up to this point being maintained at an elevated temperature below the temperature at which said shale particles tend to adhere together; confining said suspension within a cylindrical axially limited space while forming said suspension into a vortex, the rate of flow in said vortex being such that shattered particles are kept circulating within said space and thereby further comminuted; incorporating with said vortex additional fluid substantially devoid of free oxygen and sufficiently hot to maintain the temperature in said vortex at a point where said shale will be devolatilized; withdrawing from the center of Said vortex hot uid having suspended therein relatively ne particles of devolatilized shale; separating said devolatilized shale from said hot fluid, condensing the oily fraction of said uid to recover the oil content of said shale; forming the separated devolatilized hot shale into a uidized bed and burning oi the carbon content of said shale by flowing through said bed a gas preheated as recited hereinbelow and containing free oxygen; and forming the decarbonized shale into a fluidized bed by flowing a gas containing free oxygen through said bed of decarbonized shale whereby said gas is preheated; said hot fluid and said hot gas introduced into the vortex chamber containing heat derived from said combustion.

ELMORE S. PETTYJOHN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,257,907 Griswold Oct. 7, 1941 2,285,276 Hemminger June 2, 1942 2,515,542 Yellott July 18, 1950 2,544,843 Leffer Mar. 13, 1951 FOREIGN PATENTS Number Country Date 487,983 Great Britain June 29, 1938 

1. THE METHOD OF RECOVERING OIL FROM COARSELY FRAGMENTED OIL SCALE WHICH COMPRISES PROVIDING A SOURCE OF HOT FLUID SUBSTANTIALLY DEVOID OF FREE OXYGEN AND CAPABLE OF BEING EXPANDED WITH A PRESSURE DROP OF AT LEAST 15 LBS. PER SQUARE INCH; CONTINUOUSLY AND UNINTERRUPTEDLY DISCHARGING SAID FLUID FROM SAID SOURCE WHILE CONFINING THE DISCHARGED FLUID SO THAT THE DISCHARGED CONFINED FLUID WILL FLOW AT A SUBSTANTIALLY UNIFORM VELOCITY LESS THAN THE CRITICAL VELOCITY WITH A PRESSURE DROP LESS THAN THE CRITICAL PRESSURE DROP; THEREAFTER CONTINUOUSLY AND UNINTERRUPTEDLY FLOWING SAID DISCHARGED FLUID THROUGH A SHAPLY RESTRICTED AREA SO AS SUDDENLY TO ACCELERATE SAID FLUID TO CRITICAL VELOCITY BY INSTANTANEOUSLY REDUCING THE FLUID PRESSURE BY AT LEAST 15 LBS. PER SQUARE INCH; CONCURENTLY, CONTINUOUSLY AND UNINTERRUPTEDLY INTRODUCING SAID SHALE, IN THE FORM OF GRANULES CAPABLE OF FREELY PASSING THROUGH SAID RESTRICTED AREA, INTO SAID FLOWING CONFINED FLUID UPSTREAM OF SAID RESTRICTED AREA; CONTROLLING THE FLOW OF SAID CONFINED FLUID FROM THE POINT OF INTRODUCTION OF SAID SHALE TO SAID RESTRICTED AREA SO THAT SAID SHALE WILL BE ENTRAINED BY SAID FLUID; ADJUSTING THE AMOUNT OF SHALE INTRODUCED INTO SAID FLUID TO A VALUE LESS THAN 10 PARTS BY WEIGHT FOR EACH PART OF FLUID; SAID SHALE GRANULES BEING SUBJECTED WHILE ENTRAINED TO THE FIRST ACCLERATION TO CRITICAL VELOCITY OF SAID FLUID AS SAID FLUID FLOWS FROM SAID SOURCE TO AND THROUGH SAID RESTRICTED AREA WHEREBY SAID GRANULES ARE SHATTERED AND THERE IS FORMED A RAPIDLY FLOWING SUSPENSION OF SHATTERED PARTICLES IN EXPANDED FLUID; SAID SHALE UP THIS POINT BEING MAINTAINED AT AN ELEVATED TEMPERATURE BELOW THE TEMPERATURE AT WHICH SAID SHALE PARTICLES TEND TO ADHERE TOGETHER; CONFINING SAID SUSPENSION WITHIN A CYLINDRICAL AXIALLY LIMITED SPACE WHILE FORMING SAID SUSPENSION INTO A VORTEX, THE RATE OF FLOW IN SAID VORTEX BEING SUCH THAT SHATTERED PARTICLES ARE KEPT CIRCULATING WITHIN SAID SPACE AND THEREBY FURTHER COMMINUTED; INCORPORATING WITH SAID VORTEX ADDITIONAL FLUID FORMED AS COMBUSTION GAS DURING THE SUBSTANTIALLY DEVOID OF RECITED HEREINBELOW AND SUBSTANTIALLY DEVOID OF FREE OXYGEN AND SUFFICIENTLY HOT TO MAINTAIN THE TEMPERATUE IN SAID VORTEX AT A POINT WHERE SAID SHALE WILL BE DEVOLATILIZED; WITHDRAWING FROM THE CENTER OF SAID VORTEX HOT FLUID HAVING SUSPENDED THEREIN RELATIVELY FINE PARTICLES OF DEVOLATILIZED SHALE; SEPARATING SAID DEVOLTILIZED SHALE FROM SAID HOT FLUID; CONDENSING THE OILY FRACTION OF SAID FLUID TO RECOVER THE OIL CONTENT OF SAID SHALE; AND FORMING THE SEPARATED DEVOLATILIZED HOT SHALE INTO A FLUIDIZED BED AND BURNING OFF THE CARBON CONTENT OF SAID SHALE BY FLOWING THROUGH SAID BED A GAS PREHEATED AS RECITED HEREINBELOW AND CONTAINING FREE OXYGEN; AND FORMING THE DECARBONIZED SHALE INTO A FLUIDIZED BED BY FLOWING A GAS CONTAINING FREE OXYGEN THROUGH SAID BED OF DECARBONIZED SHALE WHEREBY SAID GAS IS PREHEATED. 